Filipino experts have stressed the need for President Rodrigo Duterte to adopt "consistent and coherent” communications after his responses to statements from the United States and the United Nations caused a stir in international media.

Over the past month, Duterte has declared that his administration would pursue an "independent foreign policy”, threatened to withdraw the country from the UN, and called from U.S. Special Forces to leave the troubled southern Philippines island of Mindanao.

The comments came after the U.S. and UN expressed concern about reported extrajudicial killings taking place in the Philippines under a campaign against illegal drugs that has seen the killing of more than 3,000 suspects in less than three months.

Jean Franco, professor of political science at the University of the Philippines, warned that "recent faux pas” had already affected Duterte's political capital, which she described as being crucial for his government to garner the support of Filipinos.

"I guess, it has affected his political capital already in a sense that some people who may have trusted him in the first place may have second doubts," she was quoted as saying by news broadcaster ABS-CBN on Saturday.

"For now, most are still having [a] wait and see attitude and sort of looking at this faux pas as a learning curve on the part of the president and his men. But this cannot go on for the next few months because you can say it's just a mistake, it’s the learning curve within probably the first 100 days, but if this is going to define this administration, it’s going to be very scary," she underlined.

Stressing that it would be "a pity" if people did not understand the positive efforts of the Duterte administration, she called for messages to be conveyed "consistently and coherently".

Franco said communications were the source of the majority of the challenges faced by the administration since Duterte’s inauguration June 30, singling out a controversial expletive-laden statement in which he lashed out at U.S. President Barack Obama for his perceived meddling in Manila’s drug crackdown.

The remarks caused the cancelation of the presidents’ planned bilateral meeting on the sidelines of an Association of Southeast Asian Nations (ASEAN)-East Asia summit earlier this month.

Meanwhile, a veteran public relations specialist serving as the chairman of Grupo Agatep, Inc., warned that communication errors could be "very costly” and result in "international embarrassment” and "international disrespect” for Filipinos.

"Even those who have been very rabid supporters of the president are now not exactly turning around, but they are wishing the president would be more circumspect, he would be more careful in making utterances," Carlos Agatep was quoted as saying.

Duterte, who served as the outspoken mayor of southern Davao City for 22 years, won the May 9 election on a crime-fighting campaign, and has pledged to curb corruption and criminality within three to six months.